The Ising Model on the Ring:
           Mutation versus Recombination

	   Simon Fischer and Ingo Wegener

The investigation of genetic and evolutionary algorithms on Ising model
problems gives much insight how these algorithms work as adaptation
schemes.

The Ising model on the ring has been considered as a typical example
with a clear building block structure suited well for two-point
crossover. It has been claimed that GAs based on recombination and
appropriate diversity-preserving methods outperform by far EAs based
only on mutation.

Here, a rigorous analysis of the expected optimization time proves
that mutation-based EAs are surprisingly effective. The (1+lambda)EA
with an appropriate lambda-value is almost as efficient as usual GAs.
Moreover, it is proved that specialized GAs do even better and this
holds for two-point crossover as well as for one-point crossover.

Keywords: Ising model, mutation vs. recombination, expected
optimization time, fitness sharing